Hi there, Im new on the forum and hope anyone can help me out with this problem.

My Waeco Coolfreeze cf110 just stopped running on 230 V.
The compressor tries to start but stops after half a second, after which the error light at the display flashes red, then the green led lights up again, and after a few seconds the process starts over again.

On 12V everything works fine.

Both with 12V and 230V input the controller delivers 11,95 V to the A&C pins.

There is one big and three smaller capacitors.
The 330 uF capacitor is tested off the board and found ok.
The three smaller capacitors I left on the board. Two measured 26,9 V, one measured 26,7 V on the pins. (230 V input)
Different results with 12 volt input: two of them 12,54 V and one measures 12,32 V (12 V input)

these are all just observations. the problem is the compressor will not run on 230 V.

I know the easy solution is to buy an adapter, but it would be more practical and so much nicer to fix this.
Anybody knows this problem and knows the solution?

Laura

 

Clearly on 230v the PSU can't provide enough output current. What is the voltage on the 12v output when the compressor starts on 230v? I suspect it collapses, then after a while increases, compressor starts and so on...

I doubt its a capacitor problem. Can you take some good clear close-up vertical shots of the board from above and underneath so we can assess the circuit layout. Also do a good visual inspection to see if there are any obviously burnt or discoloured components...

 

Hi Irving, It does exactly what you say, it drops, increases, drops again.

There's nothing special to see about the board. it has no burns or discoloured components. I made some pictures.. my phone not so good in close up.

 

Hi Laura

I thought it might. Something has failed in the 230v bit. The trick is to figure out what.

Can you take another photo looking straight down on the board, as close as you can (or maybe two halves).

 

The 330 uF capacitor is tested off the board and found ok.

Did you mesure its ESR?

 

Hi Alec_t,

I took it to the shop, they mesured it for me. Told me it was in very good condition.wouldn't sell another to me, as this was still good. So can't tell you anything about the ESR....

 

Thought theres a chance, i doubt thats the problem. The external 12.24v is fed into the 230v buck converter output and I'm guessing from what I see theres a buck/boost converter on the output to give a reasonably constant 12v out for 10 - 28v in from the battery and a nominal 24v out from the 230v (12-ish on 100v AC) converter. but although it producing 26v out its not able to sustain that on load. that suggests, from experience, a feedback winding or the inverter is running at a higher frequency than expected. So we need to take some measurements. The difficulty is that PCB is heavily conformally coated and i'd like to avoid damaging that else corrosion will set in quite quickly given where the location is...

 

If you are going to try & repair this, then you need to know how the system works. The failure of the 240V ac side is common & hardly worth repairing. Easier to just use it on 12V & use a external powersupply. Heres the basic block diagram of the unit from Danfoss. The 27 - 45V DC varies depending on the selected compressor speed..

 

If you are going to try & repair this, then you need to know how the system works. The failure of the 240V ac side is common & hardly worth repairing. Easier to just use it on 12V & use a external powersupply. Heres the basic block diagram of the unit from Danfoss. The 27 - 45V DC varies depending on the selected compressor speed..

Thanks for that and the great photos. My guesswork wasn't far off then. I'm inclined to agree with you, a 230v/24v or 230/12v PSU based on an old server PSU are cheap as chips and very reliable. Since it runs off cigar lighter it must be <100W or so, so even the 12v output of a repurposed ATX PSU would do, or possibly a 90W laptop adapter at a push.

 

I guess you are right and I should give up. I'll put it back together and buy an external powersupply.
Thanks for thinking along.

 

My unit the two primary 240V MOSFETS had holes blown out. I just used an external 12v 6A powersupply.

 

Without any obvious failure mechanism, diagnosing the fault remotely is going to be tricky... though we've had a few successes here recently...

 

Maybe good to know for people who are looking for an affordable powersupply: the Mestic 12V adapter has a compatible connector with waeco coolfreeze, for just €25. It is 6A, and did not get too warm running for a few hours non stop.